British, informal, American & Australian, informal

to suddenly lose the energy or interest to continue doing what you are doing.

She'd been talking for two hours and was just starting to run out of steam.

I worked really well for two months of the project then I suddenly ran out of gas.

• when the going gets tough
• when the spirit moves
• when the spirit moves you
• when was a mere twinkle in father's eye
• when was a mere twinkle in their father's eye
• when was a twinkle in father's eye
• when was a twinkle in their father's eye
• when your ship comes in
• where is coming from
• where someone is coming from
• Where's the beef?
• Where there's a will there's a way!
• Where there's muck, there's brass.
• where there's smoke, there's fire
• whet appetite
• whether by accident or design
• whether or not
• whet someone's appetite
• which way the wind is blowing
• while away
• while away something
• while back is turned
• while someone's back is turned
• While the cat's away .
• While the cat's away the mice will play.